I found this.
It comes from this thread.
Since it is an adjustable tow hook, you don’t even have to worry about where it goes as long as you are more or less centered on the CG. That is precisely due to the fact that your cg, and your tow hook location are not actually related. Whereever you put your tow hook becomes the CG during a launch. In other words, even if your tow hook is one inch behind the CG (Say you balanced your Supra at 90mm from the LE, and the suggested location is around 104mm) If you mounted the tow hook at 104, as long as that is not behind the wings center of pressure, you will get a nice clean stable launch. The tow hook location is the CG during launch. Also, true would be if you had an unflyable CG due to all of your nose weight falling out, your launch would still go fine while under tension. As soon as tension is relaxed or released you would have an unflyable or way tail heavy glider on your hands.
So, use the suggested CG as a guide, center your hook box on that point, install, fly, and adjust. Nothing to it.